1. Field of the Invention
The present invention relates to an overload protection device of a press type switch, and more particularly to a press type switch in which a push-pull element controlling the switching of a conductive strip slides along a preset path of an 8-shaped slide groove. Accordingly, this switch has not only the function of on/off control, it can also enable the conductive strip to carry out an automatic disconnection in case of overload so that the safety of the user is ensured.
2. Description of the Prior Art
The types of switches are various. Commercially available switches like see-saw switch, press type switch, spring type switch, microswitch, etc. differ from one another in configuration which are designed to meet the using requirements and habits of the users. Regarding the technical features of the see-saw switch, the inventor of the present invention has disclosed a few previously approved cases so that it won""t be described more hereinafter. The present invention is an improvement of the two-stage press switch. A conventional two-stage press switch, as shown in FIGS. 1 through 4, utilizes a two-stage press element 2 projecting above the housing 1 to move a push rod 21, thereby controlling the conductive strip 3 in a connection or disconnection state. The press element 2 includes a heart-shaped slide groove 22 at inner side thereof which has several slide rails of different height and a U-piece 23. The top of the U-piece 23 is pivotably connected to the housing I while the bottom thereof is situated in the slide groove 22. When the press element 2 is pressed downwards, the top of the slide groove 22 is engaged at bottom end of the U-piece 23, as shown in FIGS. 1 and 2. At this time, it shows the on-state. In case of overload of the conductive strip 3, the press element 2 can""t be automatically escaped since it is located by the U-piece 23. In order to switch to the off-state shown in FIGS. 3 and 4, it should be manually done. Consequently, the conventional press type switch doesn""t have the protection effect in case of overload.
It is a primary object of the present invention to provide an overload protection device of a press type switch in which the conductive strip is deformable in the contrary direction for an electric disconnection in case of overload so that the safety in use is attainable.
It is another object of the present invention to provide an overload protection device of a press type switch which can be used as a conventional on/off switch at ordinary times.